This invention relates to a deflectable catheter, and more particularly to a catheter having a handle that can be modified to be used with unidirectional and multidirectional catheters.
Steerable or deflectable tip cardiovascular catheters are useful in many applications, being a marked improvement over catheters with fixed tip curves. They are especially useful in the field of electrophysiology for performing radio frequency ablation of abnormal electrical pathways in the heart.
There are presently several useful designs of steerable tip catheters. One such steerable tip catheter is described in Reissue Pat. No. 34,502. The catheter has an elongated catheter body and tip portion that can be deflected into a semi-circle in one direction. In addition, the catheter body and tip portion can be rotated. Therefore by tip deflection, catheter rotation and catheter translation, i.e., lengthwise movement of the catheter, contact of the tip portion with most areas of a heart chamber may be made.
There are, however, structures and irregularity in the heart chambers that often make access difficult. In some cases it is necessary to reach around obstacles to contact a desired site. Moreover, it may be necessary to use a longer or shorter deflectable tip portion to reach a particular site and maintain adequate stable contact.
One early multidirectional deflectable tip catheter had a catheter body and tip with 5 lumens, i.e., a central lumen and four outer lumens disposed symmetrically around the central lumen. This catheter had four puller wires that extended through the outer lumens. The distal ends of the puller wires were attached to a ring at the tip and the proximal ends were attached to a xe2x80x9cjoy stickxe2x80x9d. The central lumen was open at its distal end and connected to a luer hub at its proximal end. This catheter had no reinforcement in its body or tip. It was not suitable for electrophysiology because it had effectively no torque transmission to the tip, which made tip rotation difficult. Moreover, the catheter body was subject to the same deflection as the tip, but to a lesser degree.
A more recent steerable catheter has a steerable tip that is controlled by a bendable control handle. Multiple puller wires connect the steerable tip to this control handle, which can be bent in any direction and can be thought of as a multiple ball joint with friction. The tip, once deflected, can be further deflected laterally by an internal stylette. The disadvantage of this catheter design is that the tip is very soft and has poor lateral stiffness due to the presence of the stylette, which cannot transmit torque effectively. Because of this, an electrode at the tip of the catheter cannot be held firmly against the myocardial wall.
Another recent steerable tip catheter comprises a deflectable tip that can be deflected in one direction by a puller wire and further deflected laterally by an internal stylette. The stylette can also be moved axially within the catheter to change the shape of the tip curvature. The disadvantage of this catheter design is that the lateral stiffness of the tip is dependent upon the stylette, which cannot transmit torque effectively. In a design wherein the tip is rotated by means of a stylette, it follows that the lateral stiffness of the tip must be less than that of the stylette alone. This is because some torque from the stylette is required to rotate the tip. Moreover, the stylet must be kept small to allow the catheter body and tip to bend and to be safe within the patient body and heart.
The invention is directed to a deflectable catheter having a conrol handle, wherein the control handle is preferably modifiable. The modifiable control handle permits the handle to be used with unidirectional and multidirectional catheters.
In one embodiment, the invention is directed to a deflectable catheter comprising an elongated, flexible tubular catheter body having proximal and distal ends and a lumen extending therethrough. A control handle is provided at the proximal end of the catheter body. The handle comprises a handle body having proximal and distal ends and comprising an outer wall and a generally hollow interior, wherein the proximal end of the catheter body is fixedly attached to the handle body. A slidable puller wire anchor is longitudinally movable within the interior of the handle body relative to the handle body and catheter body. A sleeve is slidably mounted on the exterior of the handle body. A selection pin is fixedly attached to the sleeve and extends into the interior of the handle body proximal to the slidable puller wire anchor. A puller wire having proximal and distal ends extends through the lumen of the catheter body and into the control handle. The proximal end of the puller wire is anchored to the slidable puller wire anchor, and the distal end of the puller wire is anchored in the distal end of the catheter body.
In use, proximal movement of the sleeve and selection pin relative to the handle body causes the selection pin to contact the slidable puller wire anchor and move the slidable puller wire anchor proximally relative to the handle body and catheter body. Proximal movement of the slidable puller wire anchor relative to the catheter body results in deflection of the distal end of the catheter body.
In a particularly preferred embodiment, the invention is directed to a deflectable catheter comprising an elongated, flexible tubular catheter body having proximal and distal ends and a lumen extending therethrough. A control handle is provided at the proximal end of the catheter body. The handle comprises a handle body having proximal and distal ends and comprising a barrel at the handle body""s proximal end, the barrel having proximal and distal ends, an outer wall having a plurality of longitudinal slots therein, and a generally hollow interior, and a nose piece at the handle body""s distal end, the nose piece having proximal and distal ends, an outer wall, and a generally hollow interior. The handle body further comprises a sectioned insert permanently or removably mounted, at least in part, in the distal end of the barrel and permanently or removably attached to the nose piece. The sectioned insert comprises an axis, a plurality of fins extending from the axis, thereby forming a plurality of sections, and a central groove distal to the fins. The longitudinal slots in the outer wall of the barrel correspond in number and location to the sections formed by the sectioned insert. The handle further comprises a plurality of slidable puller wire anchors, wherein each puller wire anchor is provided in one of the sections of the sectioned insert and is longitudinally movable within the interior of the handle body relative to the handle body and catheter body.
A sleeve is slidably and rotatably mounted on the exterior of the handle body. A selection pin is fixedly attached to the sleeve and extends into the interior of the handle body proximal to the slidable puller wire anchor. The catheter further comprises a puller wire having proximal and distal ends and extending through the lumen of the catheter body and into the control handle. The proximal end of the puller wire is anchored to one of the slidable puller wire anchors, and the distal end of the puller wire is anchored in the distal end of the catheter body. Additional puller wires can be provided that are attached at their proximal ends to the other puller wire anchors.
In use, rotation of the sleeve relative to the handle body causes the selection pin to rotate within the central groove. Proximal movement of the sleeve and selection pin relative to the handle body causes the selection pin to contact one of the slidable puller wire anchors and move that slidable puller wire anchor proximally relative to the handle body and catheter body. Proximal movement of the slidable puller wire anchor attached to the puller wire relative to the catheter body results in deflection of the catheter body.